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Author (up) Bahrs, S.; Goni, A.R.; Maiorov, B.; Nieva, G.; Fainstein, A.; Thomsen, C.
Title Raman-study of photoinduced chain-oxygen ordering in RBa2Cu3O7-delta Type Journal Article
Year 2003 Publication IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY Abbreviated Journal
Volume 13 Issue 2 Pages 3192-3195
Keywords
Abstract We investigated Raman-forbidden signals in RBa2Cu3O7-delta with R = Y or Pr, which lose intensity under illumination at low temperatures. These defect-induced,peaks are only visible in oxygen-deficient material and for light polarized parallel to the copper-oxygen chains along the material's b-axis. In a first, two-laser based experiment we established that the bleaching effect of the light is polarization dependent as well. From this and other known properties we conclude that the signal is connected to the copper-oxygen chains, reflecting their state of disorder, and is thus closely related to aging and to the persistent photoconductivity effect in the material. In a second set of experiments we followed the temperature dependence of the Raman spectra and the intensity decrease.
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ISSN 1051-8223 ISBN Medium
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Notes ISI:000184242400193 Approved no
Call Number BT @ hernan @ Serial 209
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Author (up) Bahrs, S.; Goni, A.R.; Thomsen, C.; Maiorov, B.; Nieva, G.; Fainstein, A.
Title Light-induced oxygen-ordering dynamics in (Y,Pr)Ba2Cu3O6.7: A Raman spectroscopy and Monte Carlo study Type Journal Article
Year 2004 Publication PHYSICAL REVIEW B Abbreviated Journal
Volume 70 Issue 1 Pages 014512
Keywords
Abstract We investigated the time and temperature dependence of photobleaching effects in RBa2Cu3O7-delta single crystals (R=Y,Pr) by Raman spectroscopy and Monte Carlo simulations based on the asymmetric next-nearest-neighbor Ising model. In a temperature range between 40 and 300 K the bleaching slows down on cooling, displaying a pronounced change in dynamics around 160 K for R=Y. To model this behavior we extended the Ising model by introducing a single energy barrier which impedes oxygen movement in the plane unless the oxygen atoms are excited by light. We obtain a time- and temperature-dependent development of superstructures under illumination with the fastest change at intermediate model temperatures. The chain-fragment development in the simulation thus matches the experimental low-temperature dynamics of Raman photobleaching, providing further support for oxygen reordering in the chain plane being at the origin of Raman photobleaching and related effects.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121 ISBN Medium
Area Expedition Conference
Notes ISI:000222996300096 Approved no
Call Number BT @ hernan @ Serial 207
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Author (up) Bahrs, S.; Goni, A.R.; Thomsen, C.; Maiorov, B.; Nieva, G.; Fainstein, A.
Title Rare-earth dependence of photoinduced chain-oxygen ordering in RBa2Cu3O7-x (x approximate to 0.3) investigated by Raman scattering Type Journal Article
Year 2002 Publication PHYSICAL REVIEW B Abbreviated Journal
Volume 65 Issue 2 Pages 024522
Keywords
Abstract We investigated a set of oxygen – deficient RBa2Cu3O7-x (xapproximate to0.3) ceramic samples with Raman spectroscopy under resonant conditions for the defect-induced Cu-O chain related modes at 230 and 600 cm(-1). Emphasis was laid on the frequency and intensity of the modes for different rare-earth atoms, and especially on their dependence under illumination. The modes display photoinduced bleaching for all R, including the nonsuperconducting R = Pr. The dynamics of their bleaching following a temperature quench indicates similar complex relaxation processes for all samples. A simple stretched exponential with a common beta = 0.36+/-0.04 and a distribution of time constants ranging from 50 to 1400 s describes our data well. We discuss our results in connection to photoinduced chain-oxygen ordering in oxygen-deficient superconductors.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121 ISBN Medium
Area Expedition Conference
Notes ISI:000173213100111 Approved no
Call Number BT @ hernan @ Serial 213
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Author (up) Bahrs, S.; Guimpel, J.; Goni, A.R.; Maiorov, B.; Fainstein, A.; Nieva, G.; Thomsen, C.
Title Persistent photo-excitation in GdBa2Cu3O6.5 in a simultaneous Raman and electrical-transport experiment Type Journal Article
Year 2005 Publication Physical Review B Abbreviated Journal Phys. Rev. B
Volume 72 Issue 14 Pages 144501
Keywords
Abstract We investigate the connection between persistent illumination-induced effects in underdoped RBa2Cu3O7-delta known as persistent photoconductivity and Raman bleaching. Despite the long-standing assumption that the electrical and optical properties respond to the same light-induced change in the material, they have not been directly compared until now. We present a simultaneous experiment of Raman spectroscopy and electrical transport under visible illumination at low temperatures. The time dependence of the response in the two methods differs by two orders of magnitude, showing that the effects are connected but not identical. We discuss our results within the oxygen-vacancy reordering model of photobleaching and find that different Cu-O chain lengths affect the optical and the electrical response differently. Raman bleaching and persistent photoconductivity thus provide a different perspective on the microscopic oxygen vacancy distribution.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121 ISBN Medium
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Notes ISI:000232934100060 Approved no
Call Number BT @ hernan @ Serial 204
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Author (up) Correa, V. F; Villagrán Asiares, A. G.; Betancourth, D.; Encina, S.; Pedrazzini, P.; Cornaglia, P.S.; García D.J.; Sereni, J. G.; Maiorov, B; Caroca-Canales, N; Geibel, Ch.
Title Strong magnetoelastic effect in CeCo1−xFexSi as Néel order is suppressed Type Journal Article
Year 2019 Publication Physical Review B Abbreviated Journal Phys. Rev. B
Volume 100 Issue Pages 184409
Keywords
Abstract A very strong magnetoelastic effect in the CeCo1−xFexSi alloys is reported. The strength of the magnetostrictive

effect can be tuned upon changing x. The moderate low-temperature linear magnetostriction observed at low

Fe concentrations becomes very large (L

L (16T, 2K) = 3 × 10−3) around the critical concentration xc ≈ 0.23 at

which the long-range antiferromagnetic order vanishes. Upon increasing doping through the nonmagnetic region

(x > xc), the magnetostriction strength gradually weakens again. The interplay between magnetic order and the

Kondo screening appears to cause an enhanced valence susceptibility slightly changing the Ce ions valence,

ultimately triggering the large magnetostriction observed around the critical concentration. Previous studies

of the evolution of the lattice parameters with x as well as magnetization and x-ray absorption spectroscopy

measurements support this hypothesis.
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Call Number BT @ victor.correa @ Serial 842
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Author (up) Decca, R.S.; Drew, H.D.; Maiorov, B.; Guimpel, J.; Osquiguil, E.
Title Photoinduced superconducting nanowires in GdBa2Cu3O6.5 films Type Journal Article
Year 1998 Publication Applied Physics Letters Abbreviated Journal Appl. Phys. Lett.
Volume 73 Issue 1 Pages 120-122
Keywords
Abstract We report the fabrication of high-Tc superconducting wires by photodoping a GdBa2Cu3O6.5 thin film. An optical near-field probe was used to locally excite carriers in the system at room temperature. Trapping of the photogenerated electrons define a confining potential for the conducting holes in the CuO planes. Spatially resolved reflectance measurements show the photogenerated nanowires to be ?250 nm wide. Electron diffusion, before electron capture, is believed to be responsible for the observed width of the wires.
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ISSN 00036951 (ISSN) ISBN Medium
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Notes Cited By (since 1996): 7; Export Date: 17 April 2009; Source: Scopus; CODEN: APPLA; doi: 10.1063/1.121787; Language of Original Document: English; Correspondence Address: Decca, R.S.; Laboratory for Physical Sciences; Department of Physics; University of Maryland College Park, MD 20742, United States; References: Freyhardt, H.C., (1993) Applied Superconductivity, , See edited by DGM Informationsgesellschaft, Oberursel and references therein; Kirilyuk, A.I., Kreines, N.M., Kudinov, V.I., (1990) Pis'ma Zh. Eksp. Teor. Fiz., 52, p. 696; Kirilyuk, A.I., Kreines, N.M., Kudinov, V.I., (1990) [JETP Lett., 52, p. 49; Osquiguil, E., Maenhoudt, M., Wuyts, B., Bruynseraede, Y., Lederman, D., Schuller, I.K., (1994) Phys. Rev. B, 49, p. 3675; Kudinov, V.I., Chaplygin, I.L., Kirilyuk, A.I., Kreines, N.M., Laiho, R., L Approved no
Call Number BT @ osquigui @ Serial 377
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Author (up) Decca, R.S.; Drew, H.D.; Maiorov, B.; Guimpel, J.; Osquiguil, E.
Title Superconducting Materials Engineered Using a Near-Field Scanning Optical Microscope Type Journal Article
Year 1998 Publication Scanning Abbreviated Journal Scanning
Volume 20 Issue 3 Pages
Keywords
Abstract
Address Instituto Balseiro, Centro At
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ISSN 01610457 (ISSN) ISBN Medium
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Notes Export Date: 17 April 2009; Source: Scopus; CODEN: SCNND; Language of Original Document: English; Correspondence Address: Decca, R.S.; Laboratory for Physical Sciences; Department of Physics; University of Maryland College Park, MD, United States; References: Kudinov, V.I., Chaplygin, I.L., Kirilyuk, A.I., Kreines, N.M., Laitho, R., L Approved no
Call Number BT @ osquigui @ Serial 378
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Author (up) Decca, R.S.; Drew, H.D.; Maiorov, B.; Guimpel, J.; Osquiguil, E.
Title Superconducting Materials Engineered Using a Near-Field Scanning Optical Microscope Type Conference Article
Year 1998 Publication Scanning Abbreviated Journal Scanning
Volume 20 Issue Pages 156
Keywords
Abstract
Address
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Notes Approved no
Call Number BT @ jguimpel @ Serial 625
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Author (up) Decca, R.S.; Drew, H.D.; Maiorov, B.; Guimpel, J.; Osquiguil, E.J.
Title Inducing superconductivity at a nanoscale: Photodoping with a near- field scanning optical microscope Type Journal Article
Year 1999 Publication Journal of Microscopy Abbreviated Journal J. Microsc.
Volume 194 Issue 2-3 Pages 407-411
Keywords High critical temperature superconductors; Near-field microscopy; Photoconductivity; Photoinduced superconductivity; barium; copper derivative; gadolinium; nanoparticle; conductance; conference paper; crystal structure; crystallography; density; fiber optics; film; illumination; magnetic field; photoactivation; priority journal; reflectometry; scanning near field optical microscopy; temperature
Abstract The local modification of an insulating GdBa2Cu3O6.5 thin film, made superconducting by illumination with a near-field scanning optical microscope (NSOM), is reported. A 100-nm aperture NSOM probe acts as a sub- wavelength light source of wavelength ?(exc)=480-650 nm, locally generating photocarriers in an otherwise insulating GdBa2-Cu3O6.5 thin film. Of the photogenerated electron-hole pairs, electrons are trapped in the crystallographic lattice, defining an electrostatic confining potential to enable the holes to move. Reflectance measurements at ? = 1.55 ?m at room temperature show that photocarriers can be induced and constrained to move on a ?? 200 nm scale for all investigated ?(exc). Photogenerated wires present a superconducting critical temperature T(c) = 12 K with a critical current density J(c) = 104 A cm-2. Exploiting the flexibility provided by photodoping through a NSOM probe, a junction was written by photodoping a wire with a narrow (? 50 nm) under-illuminated gap. The strong magnetic field modulation of the critical current provides a clear signature of the existence of a Josephson effect in the junction.
Address Ctro. Atomico Bariloche and Inst. B., Comision Nac. de Energia Atomica, 8400 S. C. de Bariloche, RN, Argentina
Corporate Author Thesis
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Series Volume Series Issue Edition
ISSN 00222720 (ISSN) ISBN Medium
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Notes Cited By (since 1996): 1; Export Date: 17 April 2009; Source: Scopus; CODEN: JMICA; doi: 10.1046/j.1365-2818.1999.00540.x; Language of Original Document: English; Correspondence Address: Decca, R.S.; Laboratory for Physical Sciences; Department of Physics; University of Maryland College Park, MD 20742, United States; email: rdecca@physics.umd.edu; References: Decca, R.S., Drew, H.D., Empson, K.L., Investigation of the electric-field distribution at the subwavelength aperture of a near-field scanning optical microscope (1997) Appl. Phys. Lett., 70, pp. 1932-1934; Decca, R.S., Drew, H.D., Maiorov, B., Osquiguil, E., Guimpel, J., Photoinduced superconducting nanowires in GdBa2-Cu3O6.5 films (1998) Appl. Phys. Lett., 72, pp. 120-122; Endo, T., Hoffmann, A., Santamaria, J., Schuller, I.K., Enhancement of persistent photoconductivity by uv excitation in GdBa2Cu3O6.3 (1996) Phys. Rev. B., 54, pp. 3750-3752; Federici, J.F., Chew, D., Welker, B., Savin, W., Gutierrez-Solana, J., Fink, T., Wilber, W., Defect mechanism of photoinduced superconductivity in YBa2Cu3O6+x (1995) Phys. Rev. B, 52, pp. 15592-15597; Ginsberg, D.M., (1996) Physical Properties of High Temperature Superconductors V, , World Scientific, Singapore; Guimpel, J., Maiorov, B., Osquiguil, E., Nieva, G., Pardo, F., Interrelation between persistent photoconductivity and oxygen order in GdBa2Cu3Ox thin films (1997) Phys. Rev. B, 56, pp. 3552-3555; Kirilyuk, A.I., Kreines, N.M., Kudinov, V.I., (1990) Pis'ma Zh. Eksp. Teor. Fiz., 52, p. 696. , Frozen photoconductivity in YBaCuO films; JETP Lett., 52, pp. 49-54; Krylov, I.P., (1990) Pis'ma Zh. Eklsp. Teor. Fiz., 52, p. 1049; Mechanism for the frozen photoconductivity of YBa2Cu3O7-? JETP Lett., 52, pp. 442-446; Kudinov, V.I., Chaplygin, I.L., Kirilyuk, A.I., Keines, N.M., Laiho, R.L.E., Ayache, C., Persistent photoconductivity in YBa2Cu3O6+x films as a method of photodoping toward metallic and superconducting phases (1993) Phys. Rev. B, 47, pp. 9017-9028; Lederman, D., Hasen, J., Schuller, I.K., Photoinduced superconductivity and structural changes in high temperature superconducting films (1994) Appl. Phys. Lett., 64, pp. 652-654; Nakamura, O., Fullerton, E.E., Guimpel, J., Schuller, I.K., High Tc thin films with roughness smaller than one unit cell (1992) Appl. Phys. Lett., 60, pp. 120-122; Nieva, G., Osquiguil, E., Guimpel, J., Maenhoudt, M., Wuyts, B., Bruynseraede, Y., Maple, M.P., Schuller, I.K., Photo-induced changes in the transport properties of oxygen-deficient YBa2Cu3Ox (1992) Phys. Rev. B, 46, pp. 14249-14252; Orenstein, J., Thomas, G.A., Millis, A.J., Cooper, S.L., Rapkine, D.H., Timusk, T., Schneemeyer, L.F., Waszczak, J.V., Frequency-and temperature-dependent conductivity in YBa2Cu3O6+x crystals (1990) Phys. Rev. B, 42, pp. 6342-6362; Osquiguil, E., Maenhoudt, M., Wuyts, B., Bruynseraede, Y., Photoexcitation and oxygen ordering in YBa2Cu3Ox films (1994) Phys. Rev. B, 49, pp. 3675-3678; Tinkham, M., (1996) Introduction to Superconductivity, 2nd Edn., , McGraw-Hill, New York Approved no
Call Number BT @ osquigui @ Serial 376
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Author (up) Decca, R.S.; Drew, H.D.; Osquiguil, E.; Maiorov, B.; Guimpel, J.
Title Anomalous proximity effect in underdoped YBa2Cu3O6+x Josephson junctions Type Journal Article
Year 2000 Publication Physical Review Letters Abbreviated Journal Phys Rev Lett
Volume 85 Issue 17 Pages 3708-3711
Keywords Critical currents; Energy gap; High temperature superconductors; Magnetic field effects; Magnetron sputtering; Mathematical models; Phase diagrams; Phase transitions; Physical properties; Scanning electron microscopy; Superconductivity; Yttrium barium copper oxides; Anomalous proximity effect; Fluctuating phase models; Josephson effect; Photodoping; Josephson junction devices
Abstract Experiments were carried out to probe the underdoped insulating material by the Josephson effect. Junctions were fabricated by exploiting the capability of locally photodoping insulating RBa2Cu3O6+x (R = rare earth) material. The existence of an anomalously large proximity effect was confirmed. The critical current of the junctions was consisted with the conventional Josephson relationship.
Address Centro At
Corporate Author Thesis
Publisher American Inst of Physics Place of Publication Woodbury, NY, United States Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN 00319007 (ISSN) ISBN Medium
Area Expedition Conference
Notes Cited By (since 1996): 36; Export Date: 17 April 2009; Source: Scopus; CODEN: PRLTA; doi: 10.1103/PhysRevLett.85.3708; Language of Original Document: English; Correspondence Address: Decca, R.S.; Univ of Maryland College Park, United States; References: Ginsberg, D.M., (1996) Physical Properties of High Temperature Superconductors V, , World Scientific, Singapore; Zhang, S.C., (1997) Science, 275, p. 1089; Emery, V.J., Kivelson, S.A., (1995) Nature (London), 374, p. 434; Corson, J., (1999) Nature (London), 398, p. 291; Renner, Ch., (1998) Phys. Rev. Lett., 80, p. 149; Demler, E., (1998) Phys. Rev. Lett., 80, p. 2917; Den Hertog, B.C., Berlinsky, A.J., Kallin, C., (1999) Phys. Rev. B, 59, pp. R11645; Emery, V.J., Kivelson, S.A., Zachar, O., (1997) Phys Rev. B, 56, p. 6120; Tinkham, M., (1996) Introduction to Superconductivity, , McGraw-Hill, New York; Decca, R.S., (1998) Appl. Phys. Lett., 73, p. 120; (1999) J. Microsc., 194, p. 407; Osquiguil, E., (1992) Appl. Phys. Lett., 60, p. 1627; Kudinov, V.I., (1993) Phys. Rev. B, 47, p. 9017; Decca, R.S., Drew, H.D., Empson, K.L., (1997) Appl. Phys. Lett., 70, p. 1932; Orenstein, J., (1990) Phys. Rev. B, 42, p. 6342; Nieva, G., (1992) Appl. Phys. Lett., 60, p. 2159; (1992) Phys. Rev. B, 46, p. 14249; notenoteGray, K.E., (1992) Phys. Rev. B, 45, p. 10071; Pauza, A.J., (1997) J. Appl. Phys., 82, p. 5612; Katz, A.S., Woods, S.I., Dynes, R.C., (2000) J. Appl. Phys., 87, p. 2978; noteUR – http://www.scopus.com/scopus/inward/record.url?eid=2-s2.0-19244384844&partnerID=40 Approved no
Call Number BT @ osquigui @ Serial 373
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